Positive Correlation Between PSI Response and Oxidative Pentose Phosphate Pathway Activity During Salt Stress in an Intertidal Macroalga
Positive Correlation Between PSI Response and Oxidative Pentose Phosphate Pathway Activity During Salt Stress in an Intertidal Macroalga
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潮间带巨藻盐胁迫期间 PSI 响应与氧化戊糖磷酸途径活性之间的正相关性
DOI：
10.1093/pcp/pcu063
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发表时间：
2014-08-01
影响因子：
4.9
通讯作者：
Wang, Guangce
中科院分区：
文献类型：
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作者：
Huan, Li;Xie, Xiujun;Wang, Guangce
研究表明，光合限制和淀粉降解是对胁迫的响应；然而，两者之间的关系很少有详细描述。在本文中，评估了盐胁迫对光合作用、NADPH和总RNA水平、淀粉含量以及葡萄糖 - 6 - 磷酸脱氢酶（G6PDH）和核酮糖 - 5 - 磷酸激酶（RPK）活性的影响。在经受盐处理的叶状体中，通过光系统I（PSI）的循环电子流比通过光系统II（PSII）的电子流表现出更强的胁迫耐受性。即使线性电子流被敌草隆（DCMU）抑制，循环电子流仍然起作用。当叶状体在含有敌草隆的海水中恢复时，电子传递速率I（ETRI）随着盐度的增加而增加。这些结果表明，PSI从除PSII之外的来源接收电子。此外，在盐胁迫下，淀粉含量和RPK活性降低，而NADPH和总RNA的含量以及G6PDH的活性增加。来自淀粉降解的可溶性糖可能进入氧化戊糖磷酸途径（OPPP）以产生NADPH和5 - 磷酸核糖。数据分析表明，在盐胁迫期间，NADPH为浒苔（Ulva prolifera）中的PSI提供电子，OPPP参与胁迫响应，并且过量合成总RNA以辅助恢复。
Studies have demonstrated that photosynthetic limitations and starch degradation are responses to stress; however, the relationship between the two is seldom described in detail. In this article, the effects of salt stress on photosynthesis, the levels of NADPH and total RNA, the starch content and the activities of glucose-6-phosphate dehydrogenase (G6PDH) and ribulose-5-phosphate kinase (RPK) were evaluated. In thalli that underwent salt treatments, the cyclic electron flow through PSI showed greater stress tolerance than the flow through PSII. Even though the linear electron flow was suppressed by DCMU, the cyclic electron flow still operated. The electron transport rate I (ETRI) increased as the salinity increased when the thalli recovered in seawater containing DCMU. These results suggested that PSI receives electrons from a source other than PSII. Furthermore, the starch content and RPK activity decreased, while the content of NADPH and total RNA, and the activity of G6PDH increased under salt stress. Soluble sugar from starch degradation may enter the oxidative pentose phosphate pathway (OPPP) to produce NADPH and ribose 5-phosphate. Data analysis suggests that NADPH provides electrons for PSI in Ulva prolifera during salt stress, the OPPP participates in the stress response and total RNA is synthesized in excess to assist recovery.